Lamp with heat sink and active cooling device

ABSTRACT

A lamp comprising a light source comprising at least one solid state emitter. The lamp comprises a heat sink body in thermal communication with said light source. At least one air flow nozzle is present in the lamp to direct air flow across at least a portion of the heat sink body. The lamp further comprises an active cooling device, in which the active cooling device is in fluid communication with the at least one air flow nozzle and is configured to provide a flow of air to the at least one air flow nozzle. The lamp further comprises driver electronics configured to provide power to each of the light source and the active cooling device, wherein the driver electronics are remote from the active cooling device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and the benefit of, ProvisionalPatent Application Ser. No. 61/643,056 filed on May 4, 2012, thedisclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

The subject matter of the present disclosure relates generally to a lamphaving an active cooling device that provides air flow over a heat sinkto cool the lamp.

Lamps based on solid state light emitting sources, such aslight-emitting diode (LED)-based lamps, typically require operation atrelatively low temperatures for device performance and reliabilityreasons. For example, the junction temperature for a typical LED deviceshould be below 150° C., and in some LED devices should be below 100° C.or even lower. At these low operating temperatures, the radiative heattransfer pathway to the ambient is weak compared with that ofconventional light sources. In LED light sources, the convective andradiative heat transfer from the outside surface area of the lamp orluminaire can both be enhanced by the addition of a heat sink. A heatsink is a component providing a large surface for radiating andconvecting heat away from the LED devices. In a typical design, the heatsink is a relatively massive metal element having a large engineeredsurface area, for example by having fins or other heat dissipatingstructures on its outer surface. The large mass of the heat sinkefficiently conducts heat from the LED devices to the heat fins, and thelarge area of the heat fins provides efficient heat egress by radiationand convection. For high power LED-based lamps it is also known toemploy active cooling using fans or heat pipes or thermo-electriccoolers or pumped coolant fluid to enhance the heat removal.

However, there remains a need to devise systems for efficient removal ofheat from high power LED-based lamps, for high efficiency.

SUMMARY

In one aspect of embodiments of the invention, is provided a lampcomprising a light source comprising at least one solid state emitter.The lamp comprises a heat sink body in thermal communication with saidlight source. At least one air flow nozzle is present in the lamp todirect air flow across at least a portion of the heat sink body. Thelamp further comprises an active cooling device, in which the activecooling device is in fluid communication with the at least one air flownozzle and is configured to provide a flow of air to the at least oneair flow nozzle. The lamp further comprises driver electronicsconfigured to provide power to each of the light source and the activecooling device, wherein the driver electronics are remote from theactive cooling device.

In another aspect of embodiments of the invention is provided a lamp,comprising a light source comprising at least one solid state emitterand a heat sink body in thermal communication with said light source,and having at least one air flow nozzle to direct air flow across atleast a portion of the heat sink body. The at least one air flow nozzleis formed as an aperture in the heat sink body. The lamp furthercomprises an active cooling device, wherein the active cooling device isin fluid communication with the at least one air flow nozzle and isconfigured to provide a flow of air to the at least one air flow nozzle.The lamp further comprises driver electronics configured to providepower to each of the light source and the active cooling device, whichdriver electronics may be remote from the active cooling device.

In another aspect of embodiments of the invention is provided a lampcomprising a light source comprising at least one solid state emitter,and a heat sink body in thermal communication with the light source. Theheat sink body further comprises a plurality of fins, wherein theplurality of fins comprise a first set of fins of a relatively greateraxial length and a second set of fins of a relatively lesser axiallength, wherein the axis may be generally parallel with a longitudinalaxis of the lamp. The lamp further comprises at least one air flownozzle to direct air flow across at least a portion of the heat sinkbody, and an active cooling device, wherein the active cooling device isin fluid communication with the at least one air flow nozzle and isconfigured to provide a flow of air to the at least one air flow nozzle.The lamp further comprises driver electronics configured to providepower to each of the light source and the active cooling device, and thedriver electronics may be remote from the active cooling device.

In another aspect of an embodiment of the invention, is provided a lampcomprising a light source comprising at least one solid state emitter,and a heat sink body in thermal communication with the light source. Theheat sink body further comprises a plurality of fins, wherein a majorityof the plurality of fins are in a shadow area of the lamp. The lampcomprises at least one air flow nozzle to direct air flow across atleast a portion of the heat sink body, and an active cooling device,wherein the active cooling device is in fluid communication with the atleast one air flow nozzle and is configured to provide a flow of air tothe at least one air flow nozzle. The lamp further comprises driverelectronics configured to provide power to each of the light source andthe active cooling device, which driver electronics may be remote fromthe active cooling device.

In another aspect of an embodiment of the invention, is provided a lampcomprising a light source comprising at least one solid state emitter,and a heat sink body, the heat sink body in thermal communication withthe light source. The lamp further includes at least one air flow nozzleconfigured to direct air flow across at least a portion of the heat sinkbody, and an active cooling device in fluid communication with the atleast one air flow nozzle, which cooling device is configured to providea flow of air to the at least one air flow nozzle. The lamp furthercomprises a housing. A surface of the housing and a surface of the heatsink body form the at least one air flow nozzle. The lamp furthercomprises driver electronics configured to provide power to each of thelight source and the active cooling device, which driver electronics maybe remote from the active cooling device.

In another aspect of embodiments of the invention, is provided a lampcomprising a light source comprising at least one solid state emitter,and a heat sink body in thermal communication with the light source. Theheat sink body further comprises at least one fin having two lateralsides. The lamp includes at least one air flow nozzle to direct air flowacross at least a portion of the heat sink body, and an active coolingdevice in fluid communication with the at least one air flow nozzle. Theactive cooling device is configured to provide a flow of air to the atleast one air flow nozzle. In operation of the lamp, air is axiallydirected adjacent both lateral sides of the at least one fin. The lampfurther comprises driver electronics configured to provide power to eachof the light source and the active cooling device, which driverelectronics may be remote from the active cooling device.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 is a perspective view of a lamp of a first specific embodiment.

FIG. 2 is a front view of a lamp of a first specific embodiment.

FIG. 3 is a top view of a lamp of a first specific embodiment.

FIG. 4 is a sectional view of a lamp of a first specific embodiment.

FIG. 5 is a sectional view of a heat sink and active cooling device of afirst specific embodiment.

FIG. 6 is a sectional view of a heat sink of a first specificembodiment.

FIG. 7 is a sectional view showing cooling air flow, according to afirst specific embodiment.

FIG. 8 is another a sectional view showing cooling air flow, accordingto a first specific embodiment.

FIG. 9 is a perspective view of a lamp of a second specific embodiment.

FIG. 10 is a cutaway view of components of a lamp of a second specificembodiment.

FIG. 11 is another cutaway view of components of a lamp of a secondspecific embodiment.

FIG. 12 is a transparent sectional view of components of a lamp of asecond specific embodiment.

FIG. 13 is a perspective view of a lamp of a third specific embodiment.

FIG. 14 is a sectional view of a lamp of a third specific embodiment.

FIG. 15 shows air flow through a heat sink in accordance with a thirdspecific embodiment.

FIG. 16 is a front view of a lamp in accordance with a fourth specificembodiment.

FIG. 17 is a sectional view of a lamp in accordance with a fourthspecific embodiment.

FIG. 18 is a front view of a lamp in accordance with a fifth specificembodiment.

FIG. 19 is a cutaway front view of a lamp in accordance with a fifthspecific embodiment.

FIG. 20 is a top transparent view of a lamp in accordance with a fifthspecific embodiment.

FIG. 21 is a side closeup view of the cooperation of a fin and nozzle ofa lamp in accordance with a fifth specific embodiment.

FIG. 22 is an view of the interior of a nozzle showing a diverter.

FIG. 23 is a sectional view showing air flow from a nozzle of a lamp inaccordance with a fifth specific embodiment.

FIG. 24 is an exploded view of a lamp in accordance with a fifthspecific embodiment.

FIG. 25 is a side view of a lamp in accordance with a sixth specificembodiment.

FIG. 26 is a transparent side view of a lamp in accordance with a sixthspecific embodiment, exposing an active cooler.

FIG. 27 is a side view of a heat sink employed in a lamp in accordancewith a sixth specific embodiment.

FIG. 28 is a perspective view of a heat sink employed in a lamp inaccordance with a sixth specific embodiment.

DETAILED DESCRIPTION OF THE INVENTION

As noted, embodiments of the invention provide a lamp, comprising alight source comprising at least one solid state emitter, and a heatsink body in thermal communication with the light source. The lampincludes at least one air flow nozzle to direct air flow across at leasta portion of said the sink body, and an active cooling device, whereinthe active cooling device is in fluid communication with the at leastone air flow nozzle and is configured to provide a flow of air to the atleast one air flow nozzle. The lamp further includes driver electronicsconfigured to provide power to each of the light source and the activecooling device, and the driver electronics may be remote from the activecooling device.

As used herein, the term “lamp” may be taken as being generallyequivalent to any of the following alternative phraseology: “lightingdevice”; “lighting apparatus”; “light-emitting apparatus”; “illuminationdevice”. A “light source comprising at least one solid state emitter”typically may comprise an LED-based light engine such as an array of LEDchips or dies; a “lamp” includes further components in addition to thislight source, such as optical elements for distribution of emittedlight, a heat sink body for thermal management, and an active coolingdevice for generating a flow of cooling fluid such as air. It is to beunderstood that “air” may be replaced by any fluid which is suitable forheat dissipation.

In accordance with embodiments of the invention, a heat sink body (andany attendant heat dissipating surface area enhancing structures, e.g.,fins) may comprise one or more high thermal conductivity materials. Ahigh conductivity material will allow more heat to move from the thermalload to ambient and result in a reduction in temperature rise of thethermal load. Exemplary materials can include metallic materials such asalloy steel, cast aluminum, extruded aluminum, and copper; or the like.Other materials can include engineered composite materials such asthermally-conductive polymers as well as plastics, plastic composites,ceramics, ceramic composite materials, nano-materials, such as carbonnanotubes (CNT) or CNT composites. Other configurations may include aplastic heat sink body comprising a thermally conductive (e.g., copper)layer disposed thereupon, such as disclosed in US Patent Publication2011-0242816, hereby incorporated by reference. Exemplary materials canexhibit thermal conductivities of about 50 W/m-K, from about 80 W/m-K toabout 100 W/m-K, 170 W/m-K, 390 W/m-K, and from about 1 W/m-K to about50 W/m-K, respectively. In order to maximize light output, a heat sinkbody and/or fin may comprise a reflective layer, such as a reflectivelayer which has a reflectivity for visible light of greater than about90%. Reflective heat sinks which may be employed are those described andenabled in US Patent Publication 2012-0080699, which is herebyincorporated by reference.

In accordance with embodiments of this disclosure, any heat sink bodyand/or heat sink fin and/or heat sink finlet may individually comprise ametallic material or generally, any material having an effective thermalconductivity. For example, a heat sink may comprise regions of differingthermal conductivity. For example, it may be attractive to seat an arrayof LED chips on a board, on a region (e.g., a copper slug) comprisingcopper metal (for its very high thermal conductivity), and the regioncomprising copper metal is affixed to an aluminum heat sink (for itsacceptable thermal conductivity and acceptable cost).

The heat sink body of lamps in accordance with embodiment of thisinvention will be in thermal communication with at least the lightsource. This is for the purpose of transferring heat energy from thelight source to the heat sink body during operation of lamp, so that theLEDs may operate efficiently. The phrase “thermal communication”generally refers to heat transfer that occurs between (or among) the two(or more) items that are in thermal communication, regardless of how theheat is transferred between or among the items (e.g., conduction,convection, radiation, or any combinations thereof, directly orindirectly). In some situations/embodiments, the majority of the heattransferred from solid state light emitters is transferred to a heatsink body by conduction; in other situations/embodiments, the majorityof the heat may be transferred by convection, or a combination ofconduction and convection.

In accordance with embodiments of this disclosure, the at least oneactive cooling device may comprise at least one of synthetic jet, fan orpiezojet; or the like. As would be generally understood by personsskilled in the art, a synthetic jet typically provides an oscillatingair flow which may efficiently and effectively direct relatively coolerair from the ambient, towards the proximity of a heat sink body and/orfins, so as to carry heat away from the lamp. Many synthetic jetactuators/active cooling devices which are described in ProvisionalPatent Application Ser. No. 61/643,056 filed on May 4, 2012 (thedisclosure of which is incorporated herein by reference in itsentirety), may be employed.

In general, any active cooling device of the present disclosure (such asa synthetic jet or synthetic jet actuator) may be characterized by itsefficiency expressed in terms of flow rate of air from the coolingdevice, per watt of power input to the cooling device. The flow rate ofair is the volume of air displaced by the movement of the diaphragms ofthe cooling device, per unit time (but volume of air here typically doesnot include the volume of any entrained air). In accordance with someembodiments, the cooling device comprises a synthetic jet operating atless than about six cubic feet per minute (CFM) per watt. “Watts ofinput power” for this purpose, only refers to the power consumption ofthe cooling device itself, not necessarily the power required to operatea lamp as a whole. In other, narrower embodiments, a cooling device ofthe present disclosure may be characterized by an efficiency of lessthan about 4 CFM/W (e.g., 1-4 CFM/W), or less than about 2 CFM/W, orabout 1 CFM/W. By configuring a cooling device for such efficiencyvalues, one may achieve lower cost, through using fewer and/or lessexpensive permanent magnet(s).

Nozzles generally permit air to be alternately taken in by a syntheticjet, and then propelled from the synthetic jet, depending upon whichcycle of the “breathing” mode of operation this type of active coolingdevice is operating. In some embodiments, at least one air flow nozzleis formed as an aperture in, or is integral to, the heat sink body. Insome embodiments, at least one air flow nozzle comprises an air flowdivider which is internal to the nozzle. Such air flow divider maycomprise a wall effective to divide a flow of air, yet usually withoutcreation of significant acoustic noise when air is flowing past thedivider. In certain embodiments, such air flow divider comprises a bladeedge or ship-hull shape.

In certain embodiments, the heat sink body may further comprise aplurality of heat dissipating surface area enhancing structures such asfins (e.g., thermal fins). These may be made of the same or differentmaterial than the heat sink body. In some embodiments of the presentdisclosure, the plurality of heat dissipating surface area enhancingstructures comprise a first set of fins of a relatively greater axiallength and a second set of fins of a relatively lesser axial length.That is, if a lamp defines a generally longitudinal profile, there willbe a geometric axis to the lamp, and the two respective sets of fins aredisposed generally parallel to the axis. Their respective lengthsmeasured along the axial direction, may be different, as above. Wheresuch second set of fins are employed, they generally are disposed suchthat they do not block light emitted from the lamp, or are in the shadowof the lamp. That is, these shorter “finlets” may enhance heatdissipation from the lamp while minimizing obstruction of emitted light.As a general design principle, the number, size and shape, and geometricconfiguration of the fins in the lamp are selected to optimize highconvective heat transfer with low obstruction of light when the lamp isin operation.

In some embodiments, and independent of the presence of finlets, atleast some or a majority of the plurality of heat dissipating surfacearea enhancing structures do not block light emitted from the lamp, orare in the shadow of the lamp.

With respect to the air flow employed in many embodiments of activelycooled lamp described herein, the air flow should generally comprise aReynolds number (as defined below) which is selected to optimizehigh/maximum convective cooling with low/minimum noise from the airflow. Air flow may be selected to be turbulent, laminar, or combinationthereof.

In selected embodiments, air flow from the at least one nozzle (when thelamp is in operation), comprises a Reynolds number Re at peak air flowvelocity selected to optimize high/maximum convective cooling withlow/minimum noise from the air flow. For example, the air flow from theat least one nozzle may be characterized by a value for Re(d) (definedbelow) of from about 50 to about 800, or more narrowly, from about 100to about 350.

Inventors of the present specification has found that specified flowparameters (such as Re) for air flowing from a nozzle in an activelycooled lamp can have important technical effects. Air flow from a nozzlewith a Re value which is too high will generally result in anunacceptable acoustic noise level, while too low a value for Retypically results in insufficient cooling of an actively cooled lamp.Therefore, investigations by the present inventors have ascertainedpreferred parameters, described as follows.

As would be understood by the persons of ordinary skill in the art,Reynolds numbers for air can be calculated by a product of the fluidvelocity (U), a characteristic length (L_(char)), and the inverse of afluid kinematic viscosity (v):

Re=(U*L _(char))/v.

For an actively cooled lamp having an active cooling device (e.g., asynthetic jet), it may sometimes be convenient to determine fluidvelocity U as a ratio of the volume flow rate Q for air from thesynthetic jet, to the number of nozzles times the total area of thenozzle openings.

Note that for air as a cooling fluid, many relevant parameters (e.g.,viscosity) are known. Thus, all that is reasonably needed to measure toobtain a Re value, is the characteristic length and the fluid velocity(U). The velocity is generally measured at the egress of the relevantnozzle. However, since the velocity of air ejected from a given nozzlemay be continuously changing (e.g., in a sinusoidal manner due to thecyclic behavior of a synthetic jet), this disclosure will define peakvelocity (the maximum velocity with respect to space and with respect totime) as the relevant fluid velocity U. Peak velocity can be measured byany effective means, as would be understood by the artisan of ordinaryskill, including many known means such as hotwire anemometer, or bycalculation.

The characteristic length (L_(char)) is defined as either the hydraulicdiameter (d) of a given nozzle; or, alternatively, L_(char) is adistance (FL) from a nozzle exit to the furthest extent of an adjacentheat dissipating structure along which the air flows after leaving thenozzle. In one example, a heat dissipating structure is a fin which isproximate to a nozzle, and so therefore, FL would be measured as adistance from the nozzle to the point of the fin (e.g., its far tip)which is most distal from the nozzle. In other examples, the heatdissipating structure may have other configurations, e.g., tubes, pins,walls, prongs, etc. Regardless, FL is distance from opening of nozzle tomost distal point of the heat dissipating structure relative to thenozzle.

Note that FL is not necessarily the length of a heat dissipatingstructure itself; if a heat dissipating structure is spaced apart from anozzle, FL will be the sum of the length of the heat dissipatingstructure and the distance of the heat dissipating structure from thenozzle. In either event, FL is a characteristic length pertaining to thedistance air flow travels along a heat dissipating structure whenejected from a nozzle. Since there are two different types ofcharacteristic lengths, there are two different Reynolds numbers whichare relevant to this disclosure: Re(d) and Re(FL). The value for Re(d)is the Reynolds number using the hydraulic diameter (d) of a givennozzle as the characteristic length; and the value for Re(FL) is theReynolds number using FL as the characteristic length.

Now that the two different types of Reynolds numbers (namely, Re(d) andRe(FL)) have been defined, certain lamp embodiments with selected valuesof Re(FL) are now described. Re(FL) depends upon the use of a heatdissipating surface area enhancing structure, such as a fin. Therefore,in some embodiments, the heat sink body comprises a plurality of heatdissipating surface area enhancing structures, wherein the at least oneair flow nozzle is proximate to a selected heat dissipating surface areaenhancing structure. In such embodiment (when the lamp is in operation),the air flow along the selected heat dissipating structure ischaracterized by a value for Re(FL) of from about 500 to about 13000, ormore narrowly, from about 1200 to about 6400. In such embodiment, thelamp may further exhibit values (when in operation) for Re(d) of fromabout 50 to about 800.

Importantly, embodiments of the present invention may be capable ofachieving a noise level of about 20 dBA or less (e.g., from about 16 dBAto about 20 dBA, or from about 16 dBA to about 17 dBA), when an activelycooled lamp is driven at a power of about 27 W. Noise levels aregenerally measured in terms of sound pressure at an observer distance of1 meter. One technical effect for the selection of the above-notedReynolds numbers may include these values for acoustic noise. Anothertechnical effect may include enhanced cooling of the lamp.

In certain embodiments, the above noted ranges for Re(d) and Re(FL) aretaken as being relevant to actively cooled lamps having lumen outputequal to or greater than 1600 lumens and conforming to the ANSI A19profile; however, these ranges should not be construed as limited tosuch type of actively cooled lamp.

In accordance with some embodiments, other measures may be taken toreduce acoustic noise. In one embodiment, the lamp may comprise a heatsink body which comprises at least one curved lower edge adapted toallow air to flow around such edge with reduced air flow noise. As ageneral design principle, it is preferable that air flow, especially“turned” air flow, substantially does not turn around a sharp edge; orstated differently, any turned air flow substantially always turnsaround a rounded edge. Therefore, in accordance with some embodiments, aflow of air to the at least one nozzle is caused to turn at an angle of90° or greater, wherein this turned flow of air passes or traversesrounded edges or rounded surfaces. For example, a flow of air which iscaused to turn at an angle of 90° or greater, only encounters a roundedsurface of the lamp when it is being turned. Specifically, heat sinkbody and/or housing may typically be configured such that whenever airis turned (e.g., in any angle>90°), it should be made to flow around atleast some rounded edges; for example, whenever air must turn indirection around an angle of >90°, substantially no edges which aretraversed or passed are sharp edges. Although not limited by thefollowing theory, it is believed that rounded edges contribute toreduced acoustic noise reduction by avoiding the formation of vortices.In embodiments of the disclosure, air is generally guided gently aroundturns; in contrast, if air is guided around sharp edges, a vortex may becreated which can contribute to acoustic noise.

The driver electronics of the lamp (e.g., electronic driver(s) andcontroller(s) such as ASIC) typically are dedicated to driving andproviding the proper electrical signals for both the one or more lightsources (such as array of LED dies), and for the active cooling device.Driver electronics may typically comprise a light emitting diode (LED)power supply and a synthetic jet power supply on a single circuit board(e.g., PCB). The active cooling device may be further configured todirect an air flow for cooling the driver electronics.

In many embodiments, the driver electronics of a lamp are in a locationremote from the active cooling device. For example, if an active coolingdevice such as a synthetic jet assembly is at least partially enclosedby a heat sink body, the driver electronics for the active coolingdevice may be in a separate driver housing. In other words, the heatsink body may comprise a cavity, such as an inverted cup-shaped cavity,and the active cooling device may be disposed at least partially withinthis cavity, but the driver electronics generally are not disposed atleast partially within this cavity. In general, the active coolingdevice typically does not have its associated circuitry (e.g., ASIC) inthe same enclosure with the active cooling device. This may have thetechnical effect of allowing for miniaturization of the active coolingdevice. A smaller active cooling device, e.g., a smaller synthetic jetassembly than those heretofore available, may allow a lamp tosubstantially fit within the ANSI A19 volumetric profile.

In some embodiments, a lamp may comprise a geometric configuration whichsubstantially conforms to the ANSI A19 volumetric profile, while beingconfigured to operate on a power level greater than 15 W of input powerand possessing sufficient cooling ability for an efficiency of at least60 LPW when the lamp is in operation. In many embodiments, a lamp of thepresent invention, when in operation, may be capable of providing alumen output of 1600 lumens or greater (e.g., greater than 1700 lumens),when operating on a power level greater than 15 W (e.g., greater than 20W) of input power. These parameters are technical features of many ofthe embodiments of the invention, such as those described hereinbelow.However, embodiments of the invention and the principles of its designand operation are not limited to the A19 lamp envelope. Rather, they areapplicable to all suitable lamp profiles globally. Illustratively, suchlamp envelopes may include: A series (e.g., A19), B series, C-7/Fseries, G series, P-25/PS-35 series, BR series, R series, RP-11/Sseries, PAR series, T series, and MR-n series.

As would be understood by persons of skill in the art, it is usual for alamp based upon solid state light emitting sources to have a lifetimemeasured as “L70”, which refers to a number of operational hours inwhich the light output of the lamp does not degrade by more than 30%.Therefore, embodiments of the present disclosure may provide an expectedL70 lifetime of at least about 25000 hours, preferably up to about 50000hours.

Typically, a lamp may include a driver housing which can be constructede.g., from a plastic material, which facilitates the manufacture offeatures such as air flow nozzles, if present in this driver housing. Adriver housing may be connected with a base (e.g, an Edison base) thatmay include threads for connection into a conventional socket to provideelectrical power to operate lamp. Other constructions may also beemployed for connecting a lamp with a power source as well.

In many embodiments, the lamp may further comprise one or more opticalelement for distributing light. As used herein, the term “opticalelement” may generally refer to a combination of diffuser(s), anyreflector(s), and any associated light management facility(ies) (e.g,lenses). In many embodiments, an optical element may comprise adiffuser/and or reflector. Any of the diffusers described herein,regardless of shape or construction, may exhibit a white appearance whenthe lamp is not operating.

Typically, the one or more optical element is configured to provide asubstantially uniform omnidirectional light distribution from the lampwhen the lamp is in operation. For example, such a substantially uniformomnidirectional light distribution provides illumination across alatitude span of from 0° to 135° which is uniform in intensity withinabout +/−20%.

The term “omnidirectional” with respect to light distribution may bedescribed or defined in contemporaneous Energy Star guidelines, or e.g.,refers to a light distribution which varies in intensity by a value ofno more than +/−about 20% from any point taken from the zenith of alamp, to a point disposed at an angle of about 135° from the zenith.Many optical elements which are described in Provisional PatentApplication Ser. No. 61/643,056 filed on May 4, 2012 (the disclosure ofwhich is incorporated herein by reference in its entirety), may beemployed. Other possible optical element may be any of those which aredisclosed in the following commonly owned US patent applications, eachof which is hereby incorporated by reference in the entirety: U.S.patent application Ser. No. 13/189,052, filed 22 Jul. 2011 (GE Docket254037); U.S. patent application Ser. No. 13/366,767, filed 6 Feb. 2012(GE Docket 256707); US patent Publication 2012-0080699, published 5 Apr.2012 (GE Docket 245224); 2011-0169394, published 14 Jul. 2011 (GE Docket241019); US patent Publication 2011-0080740, published 7 Apr. 2011 (GEDocket 240966).

Referring now to FIGS. 1 and 2, these figures refers to a firstembodiment of an actively cooled lamp 1000 in accordance with thisdisclosure. FIG. 1 is a perspective line view of the exterior of suchlamp 1000, hereinbelow described from a top end T to a bottom end B.Note that the top end T and bottom end B are only used for convenience′sake, since lamp 1000 may be used in any orientation. FIG. 2 is anisometric side view of such lamp 1000. Lamp 1000 is seen to comprise adiffuser 1001 of generally curvilinear outline (shown here assubstantially ovoid in shape and having an axis of rotational symmetrywhich is parallel and/or coincident with an axis of lamp 1000; see lineA-A in FIG. 1), which functions to diffuse and distribute light emittedfrom one or more solid state light sources (not specifically shown),such as an array of LED dies. Typically, LED devices or chips may bemounted on a circuit board, which is optionally a metal core printedcircuit board (MCPCB). In many embodiments, all of the solid state lightemitting sources may be inorganic light emitting diodes, although it ispossible in certain embodiments to replace some or all of these withother solid state light emitting sources such as solid state lasers ororganic electroluminescent devices (OLED).

A plurality of light emitting diode (LED) devices are typically selectedto provide light which appears white. That, is, one or more LED chipsmay be selected having respective spectra and intensities that arecapable of being mixed to generate white light of a desired colortemperature and color rendering ability. For example, one or more LEDsmay emit substantially red light, while one or more other LEDs may emitsubstantially green light, while one or more yet further LEDs may emitsubstantially blue light. There are numerous other configurations ofLEDs to achieve white light which would be readily apparent to theperson having skill in the art, such as configurations which employphosphor coating either in proximity to at least one LED and/or phosphorcoating remote from at least one LED. For example, a lamp may employ atleast one blue LED having a YAG phosphor, or all of the LEDs in a lampmay be blue LEDs with YAG phosphor.

Elsewhere in this disclosure, the combination of a diffuser and aplurality of solid state light sources may be referred to as an “opticalelement”, and it is to be understood that what is shown here as adiffuser 1001 is merely the exterior of an optical element. As is alsodescribed elsewhere in this disclosure, there may be also numerous otherfacilities (not shown here) contained within a diffuser 1001, such asreflectors, waveguides, lenses, and/or other facilities for manipulatinglight.

Diffuser 1001 may be capable of providing substantially“omnidirectional” light, e.g., as that term may be described incontemporaneous Energy Star guidelines, or e.g., refers to a lightdistribution which varies in intensity by a value of no more than+/−about 20% from any point taken from the zenith Z of lamp 1000 to apoint disposed at an angle of about 135° from zenith Z.

With continuing reference to FIGS. 1 and 2, the diffuser 1001 isgenerally received within a thermal management system 1005, which maycomprise a heat sink having a main body 1003 and a plurality of heatradiating surface-area enhancing structures, such as fins 1002. Althougheight fins 1002 are shown here, this should not be taken as limiting, asa greater or lesser number may be employed, depending upon numerousfactors including one or more of: the amount of heat needed to bedissipated to the ambient; optimization of air flow from nozzles (to bedescribed below); and/or blockage or passage of light from the diffuser1001. Fins 1002 are generally disposed as protrusions from the body 1003and are placed in a circumferential disposition relative to the diffuser1001. In many lamp embodiments of this disclosure, fins are made to besubstantially planar and configured to lay in constant longitude planes.This has the technical effect of minimizing the impact of the fins onthe uniformity of longitudinal light intensity. In some embodiments ofthis disclosure, any heat dissipating surface area enhancing structure(e.g., fin) can be integral with the heat sink body, or can be attached(e.g., by adhesive, welding, bolts, screws, rivets, etc.) to it.Multiple fins may be provided as part of a unitary structure, asindividual structures or as any suitable combination of unitary andcombined structures.

Generally, thermal management system 1005 may comprise a material havinga high thermal conductivity, such as a metal such as aluminum and/orcopper. The body 1003 of such system 1005 may be cast from metal, andthe fins 1002 may be welded to body 1003 or similarly cast as one pieceor several pieces. In this embodiment, there may also be “finlets”(i.e., fins of lesser axial length than fins 1002) provided in aninterstitial position between some or all of fins 1002. Finlets may besized and positioned in such a manner that they are in the shadow area,i.e., they typically do not block light emission from the opticalelement or diffuser of the lamp.

Received within the body 1003 is an active cooling unit or active cooleror cooling device (not shown here since it is not visible from thisexterior view of lamp 1001), which active cooler may comprise asynthetic jet assembly. A synthetic jet provides an oscillating air flowwhich may efficiently and effectively direct relatively cooler air fromthe ambient, towards the proximity of fins 1002, so as to carry heataway from lamp 1001. To facilitate the directing of air, a plurality ofnozzles 1006 are provided in body 1003. These nozzles may be holesdrilled in, or otherwise provided as through-holes in the main body1003. The nozzles 1006 may be provided in a mid-section of the heat sinkbody 1003, as measured from the uppermost portion of the body 1003 to alowermost portion, relative to zenith Z. As shown on this embodiment,each fin 1002 may have a pair of nozzles 1006 proximate to a basal edge1002 a of each fin 1002. Their function and effect will be describedhereinbelow.

In this embodiment, a driver housing 1007, which may be of generallyfrustoconical profile, is affixed to the thermal management system 1005.Housing 1007 encloses electrical and electronic driver(s),controller(s), and associated wiring (not shown here since they areobscured by the housing 1007). The electrical and electronic driver(s)and controller(s) typically are dedicated to driving and providing theproper electrical signals for both the one or more solid state lightsources (such as array of LED dies), and for the active cooler. That is,the active cooler enclosed in body 1003 typically does not have itsassociated circuitry (e.g., ASIC) enclosed in body 1003; its associatecircuitry is rather enclosed in housing 1007 and is remote from body1003. Finally, at bottom end B of lamp 1001 is base 1008, which may be atypical Edison-base for screwing to sockets to receive electricalcurrent, or may be other base for receiving current, such as pins,prongs, bayonet bases or caps, bi-post, bi-pins; or the like.

Turning now to FIG. 3, is depicted a line drawing of a top view of thelamp 1000 of the first embodiment, showing view of top of diffuser 1001from zenith Z, and fins 1002, and a ledge of body 1003.

FIG. 4 is intended to show a cross-sectional view of lamp 1000, tovisualize the interior of diffuser 1001 and to show at least a portionof the active cooling unit 1011. The plane of cross section in FIG. 4 isone which is collinear with the major axis of lamp 1000. Although thediffuser 1001 may have many configurations as described in detailelsewhere to enable substantially omnidirectional light output, in thisembodiment diffuser 1001 encloses a reflector 1010. More particularly,this view shows an active cooling unit 1011 (e.g., synthetic jet)substantially enclosed in a cavity within heat sink body 1003.

FIG. 5 depicts a partial cross section view of a lamp of the firstembodiment, in which all components are hidden, except for the thermalmanagement system 1005 comprising a heat sink body 1003 and fins 1002,and active cooling unit 1011. The view of FIG. 6 is intended to moreclearly depict the manner in which the heat sink body 1003 is itself a“housing” for the active cooling unit 1011; that is, the active coolingunit (e.g., synthetic jet) 1011 typically does not itself have its owndedicated housing. Although not described in detail here, effectiveelectrical wiring is received in active cooling unit 1011 from thedriver electronics in housing 1007 (FIG. 1). Such wiring providescurrent with an appropriate signal to drive the actuation of the activecooling unit 1011. Also, there exists effective electrical wiringreceived in active cooling unit 1011 from the driver in driver housing1007, which then extends to the solid state light source so as to powerthe solid state light source (array of LED chips). Such wires may extendthrough the cavity which receives (or contains) the active cooling unit1011, and typically are routed around the active cooling unit 1011itself. In this embodiment, an array of LED chips/dies (not shown) ispositioned (directly or preferably indirectly) on a substantially planarupper platform 1012 of heat sink body 1003. For example, the LED chipsmay be placed on a MCPCB (metal core printed circuit board), which maybe affixed using a thermal paste. The array of LEDs are thus in thermalcommunication with the thermal management system and heat sink body1003. FIG. 6 is similar to the view of 5 except that the view of theactive cooling unit 1011 is also hidden, so as to reveal the cavity 1013within the heat sink body 1003 within which the active cooling unit 1011is substantially enclosed. Also revealed in FIG. 6 is a divider plate1014 which separates (and, e.g., electrically insulates) the activecooling unit 1011 from the housing 1007.

Turning now to FIGS. 7 and 8, these are partial depictions of lamp 1000in a simplified cross-section, showing numerous fins removed and asimplified version of the active cooling unit 1011. These latter twoFigures are intended to depict some salient features of the activecooling of the lamp when in a typical normal mode of operation. Sincesynthetic jets function in an oscillatory manner, drawing air in duringone cycle, and then expelling air out during another cycle, any givennozzle 1006 may at one time be an intake nozzle for drawing air in, andat another time be an exhaust for jetting air out. FIG. 7 shows oneportion of a cycle, where air 1020 i is taken in from the ambient (“i”for in) to a nozzle 1006 on a right hand side of lamp 1000; and, thenfrom another nozzle 1006 in a different location, cooling air is jettedor expelled so as to flow generally upwards in stream 1020 o (letter “o”for out). The smaller arrows generally parallel to the arrow for 1020 oschematically depicts air from the ambient which is entrained along withthe flow of expelled air 1020 o. Therefore, based on the position of thenozzles 1006 at the basal edge 1002 a (FIG. 1) of fin 1002, cooling air1020 o is made to flow along essentially an entire axial length of fin1002, so as to provide effective heat dissipation. FIG. 8 shows anotherportion of the cycle, in which the nozzle 1006 which had expelled air,is now the intake for air 1020 i, and the nozzle which previously drewair in, now expels air in a flow 1020 o along the length of another fin(not shown, removed for clarity).

Referring now to a second embodiment of an actively cooled lamp, FIG. 9depicts a perspective external view of an actively cooled lamp 1100,characterized at least in part by a diffuser 1101 having, in thisembodiment, a substantially toroidal shape with an axis parallel to amajor axis of lamp 1100. This view in FIG. 9 permits arrays ofindividual solid state light emitting elements (e.g. LED chips) 1112 tobe seen for explanation's sake, although in practice the diffuser willbe substantially translucent such that individual LED chips 1112 willtypically not be perceptible either when the lamp is either energized ornot energized. In this embodiment, diffuser 1101 at least partiallyencircles a heat sink body 1105, which is provided as a cast metallicbarrel substantially coaxial to the major axis of lamp 1100. That is,the heat sink body 1105 is in a central position relative to aperipheral diffuser 1101. Heat sink body 1105 is shown here as having a“snowflake” cross-section, but it is to be understood that the heat sinkbody may be any shape provided that it comprises channels 1110 a forcooling air to flow from an active cooler (1111, FIG. 12) proximate alower axial portion of heat sink body 1105, to an upper axial portion ofbody 1105.

FIG. 10 shows a portion of lamp with the diffuser and solid state lightsources hidden. For example FIG. 10 shows body 1105 as having bored orcast through holes 1114 which permit cooling air to flow from an activecooler proximate a lower axial portion of heat sink body 1105, to anupper axial portion of body 1105.

Returning to FIG. 9, the channels 1110 a are defined by the slats orfins 1110 which may extend radially (relative to a circle defined bytoroidal diffuser 1101) from body 1105. These slats or fins 1110 aresurface-area enhancing heat dissipating elements. The channels permitair ejected from nozzles 1106 to flow over substantially the entireaxial length of heat sink body 1105. The lamp 1100 comprises a pluralityof nozzles 1106 directed substantially axially upward (relative to abase 1108 being a “bottom” and a heat sink 1105 being a “top” of a lamp)to permit air to be passed through a plurality of channels 1110 a andproximate the length of slats or fins 1110. Nozzles 1106 also permit airto be alternately taken in by an active cooler (e.g., synthetic jet, notspecifically shown) and then propelled from the active cooler, dependingupon which cycle of the “breathing” mode of operation the active cooleris operating.

In a similar manner to the first embodiment described above, lamp 1100also comprises a driver housing 1107 which may enclose driver/controllerelectronics for both the active cooler and for the solid state lightsources (e.g., LED chips 1112).

The array of LED chips 1112 depicted in FIG. 9 are disposed on a lateralsurface of the substantially barrel-shaped heat sink body 1105. In thisembodiment, heat sink body 1105 has a polygonal cross section, and theLED chips 1112 are mounted, generally indirectly, on a planar side ofthis heat sink body having a polygonal cross section. For example, theLED chips may be placed on a MCPCB (metal core printed circuit board),which may be affixed using a thermal paste. Mounting may be accomplishedin any effective manner provided that efficient thermal communication isestablished between the LED chips 1112 and the heat sink body 1105. Forexample, one convenient manner in which to dispose LED chips is toprovide a plurality of LED chips premounted on a board 1113. Althoughnot specifically shown here, one embodiment comprises providing a thinflexible board 1113 onto which LED chips are premounted, which may havea thickness of 0.01 inches or less, which is then wrapped around acircumferential periphery of the heat sink, akin to a rim on a wheel.Such flexible board may be adhered to the heat sink 1105 by anultra-thin epoxy adhesive. The plurality of LED chips 1112 emit lightradially in this embodiment towards the interior of the diffuser 1101,which latter element functions to re-direct light so as to provide asubstantially uniform, preferably “omnidirectional” (as defined above)light radiating pattern from lamp 1100. For provision of electricalcurrent, a base 1108 is provided, which may be a standard Edison-typescrew base or any other effective manner of connecting lamp 1100 to anexternal source of current, such as pins or pegs.

Turning now to FIG. 11, a bottom perspective view of a portion of anactively cooled lamp in accordance with this second embodiment is shown,but with several elements hidden: diffuser, LED chips and board, andcover for active cooler. This view is intended to show the positioningof an active cooler (active cooling unit, synthetic jet) 1111beneath/below a barrel-shaped heat sink body 1105 having longitudinalchannels or through-holes 1114. While this view does not accuratelyrepresent the actual air flow from the active cooler 1111 into thechannels 1114, it is intended to be illustrative of the source of theair flow (cooler 1111) and its position of ingress into the body of theheat sink (viz., channel 1114).

FIG. 12 is a top perspective sectional view of a lamp 1100 according tothis second embodiment. In this figure, the heat sink body 1105 ischosen as having the snowflake-shaped cross section, of which 1110 isone representative slat/fin, although of course the body can be anyshape, preferably substantially cylindrically symmetrical. In thisfigure, a synthetic jet 1111 is visible. A plurality of nozzles 1106permit cooling air to be alternately pulled in to the synthetic jet andejected from the synthetic jet, depending on the stage in the cycle ofoperation of the synthetic jet. Here, an air flow into one nozzle 1106is shown as air flow 1116 on the left side of this schematic depiction;owing to the operation of the synthetic jet, a directed air flow 1117 isdirected generally upwardly from another nozzle, and then into a spacebetween the slats 1110 of this heat sink body 1105, so as to remove heatto the ambient.

FIGS. 13-15 depict various views of a third embodiment of an activelycooled lamp 1200 in accordance with certain aspects of this disclosure.In this embodiment, actively cooled lamp 1200 is characterized, in part,by an active cooler 1211 which is in a spaced-apart relationship with aheat sink 1205, to permit a greater possibility of entrainment of airinto/with air that is emitted from active cooler 1211. In particular,FIG. 13 is a top perspective line-drawing view of a lamp 1200 having aheat sink body 1205 possessing a barrel-shape with a substantiallypolygonal or annular cross section, which has an axisparallel/coincident with a major axis of lamp 1200. It is substantiallyencircled at its periphery by a substantially toroidal diffuser 1201,which re-directs light emitted from solid state light emitting elementssuch as LED dies 1212; these dies 1212 emit light within the diffuser ina substantially radially direction, which is thenmixed/diffused/re-directed to give an appropriate external lightemission, e.g., an omnidirectional light emission pattern. The LEDs 1212may be placed on a flexible board which wraps a circumferentialperiphery of the heat sink body 1205. In this regard, this thirdembodiment shares similarities to the second embodiment. However, heatsink body 1205 here does not possess through holes or channels whichpenetrate from a bottom of a heat sink body to a top of a heat sink.Rather, in this embodiment, the heat sink may comprise slats or fins1210 extending or protruding in a substantially downward axialdirection. Slats/fins 1210 may also be replaced in part or in whole by apin or pin forest or other heat-dissipating, surface area enhancingshapes.

Slats or fins 1210 are better seen in cross-sectional side view FIG. 14,in which pairs of the plurality of slats 1210 define radial channels1214. This view also depicts the positioning of heat sink body 1205 on astanchion, post, or pin 1204 so as to attain its spaced-apartrelationship from active cooler 1211. Although in this view, the activecooler 1211 is shown to be a vertically positioned synthetic jet, it mayalso be a synthetic jet positioned in any effective orientation, or anyother active cooler such as a fan or piezojet.

Although active cooler 1211 is generally substantially contained withinan enclosure, air ejected therefrom is directed towards slats 1210 andheat sink body 1205 by passage through slots 1206. FIG. 15 is a bottomperspective cutaway operational view, depicting passage of air 1217.Active cooler 1211, if operated in an oscillating mode (as would asynthetic jet), is seen to take inflowing air 1216 through one slot1206. Substantially simultaneously, ejected air 1217 flows outward fromanother slot and impinges the slats/fins 1210, and may flow into thechannels (1214; FIG. 14) defined by slats/fins 1210. The slots are shownhere as extending along a line which is substantially normal to thechannels 1214, so as to enhance “air-turning” of the ejected air, aswell as entrainment of ambient air which has not been ejected fromactive cooler 1211. However, slots above the active cooler and thechannels defined by slats can be at any effective angle relative to eachother, e.g., parallel.

Returning to FIG. 13: driver housing 1207 may enclose electroniccircuitry (not shown) for driving/controlling both the active cooler andthe plurality of LED dies 1212. Current may be provided to the LED dies1212 by extending wiring (not shown) through troughs or holes in post1204 and body 1205. Base 1208 may be an Edison base or any other basecapable of providing mains current to lamp 1200.

In this fourth embodiment, shown in side view in FIG. 16 and crosssection in FIG. 17, a lamp 1300 comprises heat dissipating surface areaenhancing structures of at least two types. These heat dissipatingsurface area enhancing structures include, in this embodiment, aplurality of fins 1302 of relatively longer axial length and a pluralityof finlets 1304 of relatively shorter axial length, wherein the numberof finlets is greater than the number of fins. In this embodiment, anactive cooler 1311 (e.g., synthetic jet) propels cooling air out throughnozzles (not shown) which comprise positions at a location proximate theaxial bottom of finlets 1304. Generally, such nozzles may be formed asholes in the driver housing 1307, rather than as apertures in heat sink1303; however, it is also possible for nozzles to be formed in anycombination of apertures in the heat sink 1303 and apertures in thedriver housing 1307. Generally, this embodiment exemplified a lampwherein nozzles may eject a cooling air stream to flow along essentiallythe entire length of at least one heat dissipating surface areaenhancing structure (e.g. a finlet 1304). In operation, the ejectedcooling air stream may entrain ambient air to increase the mass flow ofair which functions to cool the lamp.

The optical element 1301 (e.g., optical management system, which maycomprise at least a diffuser and a reflector 1310) functions, inoperation, to distribute light emitted from a plurality of solid statelight sources (e.g., LED chips, not shown). The plurality of solid statelight sources are positioned on an upper, outer surface of heat sink1303, and in thermal communication therewith. The plurality of solidstate light sources emit light in an generally axially upward fashion inthis embodiment. Generally, this embodiment exemplifies a lamp having amajority of its heat dissipating surface area enhancing structures(e.g., fins) positioned in the shadow of the light distributed by theoptical element. That is, in this embodiment, all of the finlets 1304are sized and positioned such that they do not block light emitted fromthe optical element 1301, while the optical element 1301 distributeslight in an omnidirectional fashion (e.g., a light distribution whichvaries in intensity by a value of no more than +/−20% from any pointtaken from the zenith of a lamp to a point disposed at an angle of 135°from the zenith).

In a fifth embodiment of a lamp in accordance with this disclosure, lamp1400 is depicted in a side view in FIG. 18. In this schematicembodiment, a lamp 1400 is sized and shaped to conform essentially tothe form factor of an A19 profile is provided, but it is to beunderstood that features of this embodiment, as well as the features ofthe other embodiments described in this disclosure, may independently beadapted for use in a wide variety of lamp profiles. Optical element 1401is intended to embrace a plurality of components to manage light emittedby a plurality of solid state light emitting sources (e.g., LED chips,not shown in this view). Such optical element may comprise anyconfiguration effective to disperse light emitted from LED chips,including many known configurations. In one embodiment, the opticalelement is adapted to provide a substantially “omnidirectional”distribution of light, as that term is elsewhere defined and described.Element 1401 generally comprises a dome shaped diffuser 1401 a. Althoughgenerally not visible to the eye when viewed from an exterior vantagepoint (since diffuser 1401 a may be translucent or opaque), a reflector1410 is shown in this schematic view. Reflector 1410 may act to redirectlight initially emitted in an upward axial direction, towards an obtuseangle relative to the top of the lamp. The “top” of the lamp is shown asT in this FIG. 18 for convenience, but it is to be understood that thelamp may be operated or viewed from any position.

The solid state light emitting sources (e.g., LED chips or LED array,not shown here) of lamp 1400 are the main source of heat which must bedissipated to the ambient, and so therefore such solid state lightemitting sources are mounted (generally in a substantially planarconfiguration) in thermal communication with heat sink 1403, preferablyat an substantial zenith of the heat sink 1403 and disposed below anaxis of reflector 1410. Extending from heat sink 1403 are a plurality offins 1402 (e.g., thermal fins or heat dissipating surface area enhancingstructures), which comprise a thin arcuate shape. The fins 1402 may bedescribed as spaced apart from each other along a circumferentialdirection of the heat sink 1403. As also described elsewhere, fins areconfigured to facilitate the conduction of heat from the heat sink tothe ambient. Although a given number of fins may be deduced from thisand other figures of this embodiment, it is to be noted that the numberof fins is not strictly limited.

Also protruding from heat sink 1403 are a plurality of (optional)finlets 1404, which may be defined as heat dissipating surface areaenhancing structures akin to a fin, but with a lesser axial lengthdimension than fins 1402. That is, one may describe the pattern shown in18 as having a plurality of relatively long fins and a plurality ofrelatively short fins (i.e., these being the finlets). In thisembodiment, the finlets 1404 are seen to alternate circumferentiallywith the fins 1402, although they may coexist in any pattern or beabsent. The axial dimension of fins 1402 is usually sufficient to extentfrom a base of heat sink 1403 to a region proximate a diffuser 1401 a.

Although not visible in the view of FIG. 18, an active cooling device(e.g., synthetic jet) is received within a cavity defined by an interiorof heat sink 1405. The active cooler may be any known active cooler,such as a fan, but is more usually a synthetic jet. The active cooler oflamp 1400 (in operation) creates an air flow which (after appropriatediversion) is propelled to flow (at least in part) in an axial directionfrom a bottom lip of the heat sink 1403 along substantially the fulllength of at least one fin 1402 (as will be described in greater detailbelow in reference to FIGS. 21-23). Preferably, air flow is propelled toflow (at least in part) in an axial direction from a bottom lip of theheat sink 1403 along substantially the full axial length of the heatsink.

A housing (e.g., driver housing) 1407, which may be made at least inpart of a plastic or polymeric material, is positioned below the heatsink and exists to enclose and protect driver and electronic controllercircuitry (not shown) used to drive and control the solid state lightsource (e.g., LED chips) and the active cooler. The housing 1407 isgenerally of an inverted frustoconical shape, with its annular baseproximate to the heat sink.

Importantly, in this embodiment, nozzles or apertures from which air maybe ejected, are generally not wholly formed as holes in either heat sink1403 or housing 1407. Rather, the nozzles may be formed as a gap createdafter housing 1407 and heat sink 1403 are mated, joined, or affixed. Thegaps are better seen from the top view of FIG. 20 as element 1405 a. Tofacilitate the formation of gaps, the housing 1407 may comprise at leastone notch 1406 in a region of the housing 1407 which is proximate tobottom of heat sink 1403, each of which notch 1406 is axially beneath afinlet 1404. The notches 1406 in the housing 1407 alternate with regularportions 1405 of the housing 1407; that is, the notches 1406 are anirregular inward deviation from the regularity of the invertedfrustoconical profile of housing 1407, while the regular portions aremerely the residual portion 1405 of the housing which maintains thisprofile. In this embodiment, each regular portion 1405 is axiallybeneath a fin 1402. Although not visible in this view, cooling air mayflow axially along an interior surface of a regular portion 1405. Lamp1401 is provided with mains current by a base 1408, shown here as anEdison base, although it is not limited to this type of base.

FIG. 19 is a side view of a lamp 1400 with housing 1407 removed fromview, so as to reveal a lower portion of an active cooler 1411. Althougha majority of the active cooler 1411 along an axial length dimension maybe enclosed by heat sink 1403, a small portion of active cooler mayextend into an interior of housing 1407. Also revealed in this view arefemale apertures 1412 along a bottom rim or lip of heat sink 1403, whichact to receive suitable male projections from an interior surface ofhousing 1407. That is, housing 1407 and heat sink 1403 generally mate(e.g., snap fit, e.g., a one way snap fit) in this embodiment, andapertures 1412 facilitate this. Of course, this disclosure is notlimited to this particular manner of affixing housing 1407 to heat sink1403, as one may contemplate other manners of affixing, including thosewhich employ grooves, notches, friction fit, threading, screws, bolts,adhesives, or any appropriate connecting means. Finally, 1413 is aschematic depiction of a driver/controller chamber.

FIG. 20 is a top view of lamp 1400, but with the optical element 1401(i.e., including 1401 a, 1410) removed. This reveals a mounting area1414, upon which may be mounted a plurality of solid state lightemitters (e.g. LED chips; not specifically shown), generally disposed toradiate light axially upward towards top T (FIG. 18). Mounting area1414, which itself may be a planar shelf at a zenith of the heat sink1403, is in thermal communication with heat sink 1403, so that heat sink1403 acts as the primary intended conduit for conducting heat away fromthe plurality of solid state light emitters. Also visible in the topview 20 is the plurality of fins 1402 and finlets 1404, seen in axialcross section. Each fin 1402 bisects or traverses a gap 1405 a which isdefined by the interior surface of regular portion 1405 of the housing1407. In operation of the lamp, cooling air (not shown) is ejectedthrough gap 1405 a (or alternately is taken into a gap 1405 a and isejected through that same gap 1405 a, if the active cooler is asynthetic jet).

FIG. 21 is a perspective close-up view of lamp 1400 at the juncture ofthe heat sink 1403 and housing 1407, showing in better detail how gaps1405 a are formed by cooperation between the bottom edge of heat sink1403 and regular portion of housing 1407. Note that air flow is shown asaxial arrows emanating in a generally upward direction, to flow (atleast in part) in a pathway adjacent a side of a fin 1402. Ultimately,air is made to flow along essentially the entire axial length of fin1402. In this embodiment, air flows generally upwards on both sides offin 1402 from each gap 1405 a. That is, when a gap 1405 a is acting as anozzle for ejected air, it may be positioned to allow air to flow in anaxially upwards pathway adjacent both lateral sides of a fin 1402.

FIG. 22 depicts a view of the interior contour of housing 1407 at alocation adjacent to the annular “base” of the inverted frustoconicalshaped housing. It is an expanded view of an interior surface of regularportion 1405 (seen from the exterior in FIGS. 18 and 21), as well aspart of an interior surface of notch 1406. Importantly, the gap 1405 ais divided at its interior into two regions by a diverter 1415, whichmay comprise a blade edge 1416. The bladed diverter 1415 acts (inoperation) to divert air flow propelled from an active cooler into twoseparate streams, as air flow impinges blade edge 1416; the division ofair flow is schematically depicted in FIG. 22 by a single upward arrowand two angled arrows. One possible technical effect enabled by theprovision of a bladed air flow diverter is to significantly reduceacoustic noise as air passes through and out from gap 1405 a. In fact,such or similar bladed air flow diverter may be employed within a nozzlein any embodiments of the disclosure for the same purpose. A bladed airflow diverter may comprise plastic and/or metal.

FIG. 23 is a schematized view of an assembled lamp 1400 in operation,showing a region where cooling air flow is ejected from active cooler1411 to escape through gap 1405 a. Where active cooler 1411 comprises asynthetic jet, movement of diaphragms may cause air to flow around anend of a rounded lobe of heat sink 1403, impinge diverter 1415, and flowout gap 1405 a. Only one size of divided gap 1405 a is shown here. Therounded end of lobe of heat sink 1403 also may contribute to acousticnoise reduction when air flows around such end. Importantly, in thisembodiment, at least some of the air flow emanating from synthetic jet1411 must be turned in direction. Therefore, the heat sink and housingmay typically be configured such that whenever air is turned (e.g., inany angle>90°), it should be made to flow around at least some roundededges; for example, whenever air must turn in direction around an angleof >90°, substantially no edges which are traversed or passed are sharpedges. Although not limited by the following theory, it is believed thatthe rounded end of lobe of heat sink 1403 and other rounded edges,contribute to reduced acoustic noise reduction by avoiding the formationof vortices. In embodiments of the disclosure, air is generally guidedgently around turns; in contrast, if air is guided around sharp edges, avortex may be created which can contribute to acoustic noise.

The exploded view shown in FIG. 24 permits one to describe oneembodiment in which lamp 1400 may be assembled. While a specificordering is described herein, it should be understood that any effectiveorder of assembly may be employed in this and other embodiments ofactively cooled lamps of this disclosure. Generally, a mounted assembly1422 of LED chips, e.g., on a printed circuit board is placed intothermal communication with a substantially planar shelf 1414 of heatsink 1403, and the assembly 1422 is thereafter framed by mount 1423,which holds down or otherwise fastens assembly 1422 to shelf 1414. Themount may generally comprise a thermoplastic material, and mayalternatively be attached to a heat sink or shelf by a thermal processwhich partially melts a part of the mount. Alternatively, the mount maycomprise protrusions which pass through holes in the heat sink, and theportion which passes through the holes is at least partially melted tosecure the mount and the assembly of LED chips to the heat sink, withoutthe use of screws.

In certain embodiments, any plastic material which is used to form thesubstantially planar shelf 1414, the mounted assembly 1422 of LED chips,and/or the mount 1423, is selected to be partially or fully specular.

The optical element 1401 may comprise a hemispherical diffuser cap(e.g., diffuser dome 1401 a), which had been visible in other views inseveral figures described above; a reflector 1410, and a complementaryhemispherical diffuser part 1401 c having a bottom aperture sized andconfigured to encircle mount 1423. Thus, complementary hemisphericaldiffuser part 1401 c is placed over mount 1423 so that the mountedassembly 1422 of LED chips may emit light axially upwards in operationthrough the bottom aperture of complementary hemispherical diffuser part1401 c; then the circumferential rim of reflector 1410 is seated on anupper rim of complementary hemispherical diffuser part 1401 c, anddiffuser dome 1401 a is affixed to the reflector 1410 and part 1401 c.The LED chips may be within the envelope of the diffuser, or may bespaced apart from the envelope of the diffuser.

After assembling synthetic jet 1411 (not described in detail here), thesubstantially complete synthetic jet 1411 is placed into a substantiallycylindrical interior cavity (not shown) of heat sink 1403. In lamp 1400,there typically exists a divider plate 1420 to separate the syntheticjet 1411 from the electronic driver/controllers (not shown) to beenclosed by housing 1407. This divider plate 1420 is placed on a bottomend of synthetic jet 1411 after its placement into heat sink 1403. Sucha divider may avoid the possibility of blowing air unnecessarily intothe interior of the housing, and may contribute to preventing electricalshorts. Although not specifically shown, housing 1407 will encloseelectronic driver/controllers; housing 1407 will be snap-fit orotherwise securely fastened to heat sink 1403. Item 1421 is thethreading required to fasten lamp 1400 into an Edison socket.

In a sixth embodiment of an actively cooled lamp, FIGS. 25 and 26 depictschematic side views of a lamp 1500 comprising a diffuser 1501, heatsink 1503 comprising heat dissipating surface area enhancing structures1502, a compartment 1506 for an active cooler (such as synthetic jet1511), and driver housing 1507. In FIG. 26, diffuser 1501 is made to betransparent for purposes of the view. The heat sink 1503 comprises anupper portion 1504 with generally bolt shape and a lower portioncomprising parallel slats 1502 projecting downwardly. The heat sink 1503used in the embodiment of lamp 1500 is more clearly shown in front viewand perspective view FIGS. 27-28, respectively. An outer lateral surfaceof upper portion 1504 supports a plurality of solid state light emittingsources (e.g., LED chips, not shown). Diffuser 1501 comprises agenerally toroidal shape, with its concave inner surface beingessentially hollow. Light from the plurality of solid state lightemitting sources emit light radially (e.g., substantially normal tomajor axis of lamp 1500) to impinge upon an inner circumferentialsurface of diffuser 1501, and thereby be redirected. The compartment1506 is a generally truncated cylinder, with a closure at the top forseating the heat sink 1503, and an open bottom and cavity for receivingan active cooler 1511. In FIG. 26, compartment 1506 is made to appeartransparent, to expose active cooler 1511. Driver housing 1507 comprisesdriver electronics and controllers for both the active cooler 1511 andthe plurality of solid state light emitting sources.

Any of the actively cooled lamps described or suggested by embodimentsof the present disclosure, may be designed as direct “plug in”components that mate with a lamp socket via: a threaded Edison baseconnector (sometimes referred to as an “Edison base” in the context ofan incandescent light bulb); a bayonet type base connector (i.e.,bayonet base in the case of an incandescent light bulb), or otherstandard base connector to receive standard electrical power (e.g., 110volts A.C., 60 Hz in the United States; or 220V A.C., 50 Hz in Europe;or 12 or 24 or other d.c. voltage). Since many actively cooled lamps ofthis disclosure do not rely predominantly upon conduction of heat intothe lamp socket via the base, actively cooled lamps of this disclosuremay be used in any standard threaded light socket without concern aboutthermal loading of the socket or adjacent hardware.

Actively cooled lamps in accordance with embodiments of this disclosuremay be particularly well suited for retrofitting higher wattageincandescent bulbs, such as incandescent bulbs in the 60 W to 100 W orhigher range. In some aspects of the present disclosure, there areprovided actively cooled lamps that may provide lumen output of at least600 lumens, and in some embodiments at least 800 lumens, at least 950lumens, at least 1300 lumens, at least 1500 lumens, at least 1700lumens, at least 1800 lumens, or in some cases even higher lumen output.For example, certain actively cooled lamps in accordance with thepresent disclosure may output substantially the same lumens as astandard 100 watt tungsten filament incandescent lamp, but at a fractionof the power input (e.g., when driven at approximately 27 W).

In general, actively-cooled lamp embodiments of embodiments of thepresent invention are capable of simultaneously achieving all of thefollowing parameters when in operation: (1) a lumen output of 1600lumens or greater (e.g., greater than 1700 lumens); (2) a distributionof emitted light which is omnidirectional (e.g., illumination isprovided across a latitude span of from 0° to 135° which is uniform inintensity within about +/−20%); (3) a geometric configuration which fitswithin the A19 envelope (or which conforms to the ANSI A19 volumetricprofile); and (4) possesses sufficient cooling ability for an efficiencyof at least 60 LPW (e.g., >65 lumens per Watt) and/or an L70 lifetime ofat least about 25000 hours. Optionally, actively cooled lamps ofembodiments of the present invention may also further simultaneouslyexhibit a correlated color temperature for light emitted from theoptical element of from 2700 K to 3000 K. Optionally, actively cooledlamps of embodiments of the present invention may also furthersimultaneously exhibit a color rendering index for light emitted fromthe optical element of greater than about 80.

Any appearance of the phrase “solid state emitter” may be taken to meanthe same thing as “solid state light emitting source”, and vice versa.Any appearance of “synthetic jet”, without more, may be taken to meanthe same thing as “synthetic jet actuator”, and vice versa. Anyappearance of “active cooling device” may be taken to mean the samething as “active cooler”, and vice versa. Furthermore, it is to beunderstood that “air” may be replaced by any fluid which is suitable forheat dissipation.

As used herein, approximating language may be applied to modify anyquantitative representation that may vary without resulting in a changein the basic function to which it is related. Accordingly, a valuemodified by a term or terms, such as “about” and “substantially,” maynot be limited to the precise value specified, in some cases. Themodifier “about” used in connection with a quantity is inclusive of thestated value and has the meaning dictated by the context (for example,includes the degree of error associated with the measurement of theparticular quantity). “Optional” or “optionally” means that thesubsequently described event or circumstance may or may not occur, orthat the subsequently identified material may or may not be present, andthat the description includes instances where the event or circumstanceoccurs or where the material is present, and instances where the eventor circumstance does not occur or the material is not present. Thesingular forms “a”, “an” and “the” include plural referents unless thecontext clearly dictates otherwise. All ranges disclosed herein areinclusive of the recited endpoint and independently combinable. In theforegoing description, when a preferred range, such as 5 to 25 (or5-25), is given, this means preferably at least 5 and, separately andindependently, preferably not more than 25.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Accordingly, theinvention is not to be seen as limited by the foregoing description, butis only limited by the scope of the appended claims.

What is claimed is:
 1. A lamp comprising: a light source comprising atleast one solid state emitter; a heat sink body in thermal communicationwith the light source; at least one air flow nozzle to direct air flowacross at least a portion of the heat sink body; an active coolingdevice, wherein the active cooling device is in fluid communication withthe at least one air flow nozzle and is configured to provide a flow ofair to the at least one air flow nozzle; and driver electronicsconfigured to provide power to each of the light source and the activecooling device, and remote from the active cooling device.
 2. The lampin accordance with claim 1, wherein the at least one active coolingdevice comprises at least one of synthetic jet, fan or piezojet.
 3. Thelamp in accordance with claim 1, wherein the lamp further comprises oneor more optical element for distributing light, wherein the one or moreoptical element is configured to provide a substantially uniformomnidirectional light distribution from the lamp when the lamp is inoperation.
 4. The lamp in accordance with claim 1, wherein the lampcomprises a geometric configuration which substantially conforms to theANSI A19 volumetric profile.
 5. The lamp in accordance with claim 1,wherein the lamp is configured to operate on a power level greater than15 W of input power and possesses sufficient cooling ability for anefficiency of at least 60 LPW when the lamp is in operation.
 6. The lampin accordance with claim 1, wherein the heat sink body comprises acavity, and the active cooling device is disposed at least partiallywithin the cavity, and wherein the driver electronics are not disposedat least partially within the cavity.
 7. The lamp in accordance withclaim 1, wherein the at least one air flow nozzle is formed as anaperture in, or is integral to, the heat sink body.
 8. The lamp inaccordance with claim 1, wherein the heat sink body further comprises aplurality of fins, wherein the plurality of fins comprise a first set offins of a relatively greater axial length and a second set of fins of arelatively lesser axial length.
 9. The lamp in accordance with claim 8,wherein at least the second set of fins do not block light emitted fromthe lamp, or are in the shadow of the lamp.
 10. The lamp in accordancewith claim 1, wherein the at least one air flow nozzle comprises an airflow divider internal to the nozzle.
 11. The lamp in accordance withclaim 10, wherein the air flow divider comprises a blade edge orship-hull shape.
 12. The lamp in accordance with claim 1, wherein a flowof air to the at least one nozzle is caused to turn at an angle of 90°or greater, and wherein the flow of air which is caused to turntraverses a rounded surface.
 13. The lamp in accordance with claim 1,wherein air flow from the at least one nozzle, when the lamp is inoperation, is characterized by a value for Re(d) of about 50 to about800.
 14. The lamp in accordance with claim 1, wherein the heat sinkcomprises a plurality of fins, wherein the at least one air flow nozzleis proximate to a selected fin, and wherein, when the lamp is inoperation, the air flow along the selected fin is characterized by avalue for Re(FL) of about 500 to about
 13000. 15. The lamp in accordancewith claim 1, wherein the lamp possesses sufficient cooling ability foran efficiency of at least 60 LPW when in operation and/or an L70lifetime of at least about 25000 hours.
 16. (canceled)
 17. (canceled)18. A lamp comprising: a light source comprising at least one solidstate emitter; a heat sink body in thermal communication light source,the heat sink body further comprising a plurality of fins, wherein amajority of the plurality of fins are in a shadow area of the lamp; atleast one air flow nozzle to direct air flow across at least a portionof the heat sink body; an active cooling device, wherein the activecooling device is in fluid communication with the at least one air flownozzle and is configured to provide a flow of air to the at least oneair flow nozzle; and driver electronics configured to provide power toeach of the light source and the active cooling device, and optionallyremote from the active cooling device.
 19. The lamp in accordance withclaim 1, further comprising: a housing, wherein a surface of the housingand a surface of the heat sink body form the at least one air flownozzle.
 20. The lamp in accordance with claim 19, wherein a boundary ofthe at least one nozzle is defined by both a surface of the housing anda surface of a heat sink.
 21. A lamp comprising: a light sourcecomprising at least one solid state emitter; a heat sink body in thermalcommunication with the light source, the heat sink body furthercomprising at least one fin having two lateral sides; at least one airflow nozzle to direct air flow across at least a portion of the heatsink body; an active cooling device, wherein the active cooling deviceis in fluid communication with the at least one air flow nozzle, and theactive cooling device is configured to provide a flow of air to the atleast one air flow nozzle; wherein air is axially directed adjacent bothlateral sides of the at least one fin; and driver electronics configuredto provide power to each of the light source and the active coolingdevice, and optionally remote from the active cooling device.
 22. Thelamp in accordance with claim 21, wherein at least two air flow nozzlesare positioned adjacent an end of the at least one fin to direct air inan axial direction adjacent both lateral sides of the at least one fin.23. (canceled)